The invention relates to a spray mixer for mixing and spraying at least two flowable components in accordance with the preamble of claim 1.
Mixers for mixing at least two flowable components in the form of so-called static mixers are described, for example, in EP-A 0 749 776 and EP-A 0 815 929. These very compact mixers provide good mixing results, in particular also on the mixing of high-viscosity materials such as sealing compounds, two-component foams or two-component adhesives, despite a simple, material-saving design of their mixer structure. Such static mixers are usually designed for single use and are frequently used for products to be hardened in which the mixer can practically no longer be cleaned.
The components to be mixed are usually supplied to those mixers by a multicomponent cartridge. For this purpose, the mixer is arranged at a cartridge outlet opening via which the components to be mixed can be dispensed from containers of the multicomponent cartridge.
In some applications in which such static mixers are used, it is desirable to spray the two components onto a substrate after their mixing in the mixer. For this purpose, the mixed components are atomized at the outlet of the mixer by the action of a pressurized medium such as compressed air and can then be applied to the desired substrate in the form of a spray jet or spray mist. In particular more highly viscous coating media, e.g. polyurethane, epoxy resins or similar, can also be processed using these technologies.
A spray mixer for such applications is disclosed, for example, in U.S. Pat. No. 6,951,310 or in EP 2 286 925 A2. In this apparatus, a tubular mixer housing is provided which extends in the direction of a longitudinal mixer axis from a mixer start up to a distal mixer end. The mixer housing receives a mixing element for a static mixing. A sleeve is arranged at the distal end of the mixer housing and compressed air can be supplied to it via a mixer inlet for compressed air oriented perpendicular to the longitudinal mixer axis. The named sleeve and the mixer housing form a mixer passage for compressed air which is terminated in the direction of the mixer start and has a ring-shaped mixer outlet for compressed air at the mixer end which surrounds a mixer outlet opening. Compressed air which flows via the mixer passage for compressed air to the mixer outlet for compressed air and which atomizes the material exiting the mixer outlet opening is supplied via the mixer inlet for compressed air in operation of the mixer.
The supply of compressed air to the mixer inlet for compressed air takes place via a hose which is not described in more detail and which is likewise oriented perpendicular to the longitudinal mixer axis due to the named orientation of the mixer inlet for compressed air.
Such spray mixers are used in systems for mixing and spraying flowable components which are in particular used for the application of coatings in the maintenance of ship hulls, pipelines and steel constructions such as bridges. It is also necessary in this respect to coat points with difficult access. It can occur in the coating of such points that hoses or lines of the coating system such as the above-described compressed air hose get caught at projections of the component to be coated. In this respect, on the one hand, the named hoses and lines may be damaged, which results in the failure of the coating system and thus in repair costs and delays in the maintenance work. On the other hand, an operator of the coating system has to work very carefully and thus also slowly at tight points, which can result in a high time effort, and thus also cost effort, in the use of the coating system.
A spray mixer is described in U.S. Pat. No. 6,131,823 which has a handle and an outer mixer housing in the form of a sleeve. The handle and the sleeve are manufactured from aluminum. In a first work step, a mixer which is made from plastic and which is composed of an inner mixer housing and a mixing element arranged therein can be placed onto the handle. In a second work step, the sleeve can be put over the mixer and can be screwed to the handle. A compressed air passage is formed between the sleeve and the inner mixer housing and compressed air can be conducted via said compressed air passage from the handle to an outlet. The mixer is in this respect only provided for a single use, with the sleeve being used a multiple of times. The handle has ports for the flowable components and for compressed air.
U.S. Pat. No. 4,255,125 describes an atomization apparatus for a combustible material having a feed inlet for the combustible material and a further feed inlet for an atomization gas. The combustible material and the atomization gas are combined in an atomization chamber within the atomization apparatus and are subsequently conducted through a mixing element in the form of curved elements.